Just at a loss here

[Mike]

I’ve posted on my 99 Honda Accord 4cy sedan before. It’s still sitting in my driveway, and I’m not sure what to try next. Here’s the rundown:

• Originally car began stalling out intermittently. Finally stalled out for good.
• Hauled it to a dealer, who checked ignition, fuel, timing. Found the car was incorrectly timing but it wasn’t mechanical, needed a new ECU. Car was choking and not restarting because engine/spark plugs were becoming severely fouled.
• Decision was reached that installing a used ECU would be cheapest repair. I hauled it home, not knowing how easy it is to replace ECUs in these cars.
• Anyway, I double checked everything while I had it. Even checked to see if the timing belt had slipped a tooth. Couldn’t find anything wrong other than a bad catalytic converter. (CC on this car is afftermarket.) Punched a hole in it to allow exhaust gas out. Didn’t fix the problem.
• Installed a second-hand ECU and had it programmed at the dealership.
• Car started with some coughs and then idled fine. Let it idle for at least 1.5 hours to see if it would choke, it didn’t. Checked spark plugs afterwards, they weren’t fouled but the electrodes looked oily.

I didn’t mention in, but the battery had gone bad during all of this. So the car sat for a couple weeks until I got a new battery.

New battery install. Car cranks but does not restart. I remember the oily spark plugs, and install new NGKs. No start. Worried about the oil, I run a compression test. Car is compressing beautifully. I try starting fluid. Car sputters to life, but now it’s acting the exact same way it did before the ECU swap. I can only keep it running if my foot is down on the gas, trying to hold it around 5000 RPM. It won’t stay there, but it surges and lets off, and if I take my foot off the gas, it chokes and dies.

It did not do this right after the ECU swap. It is doing it now, acting just as it did before the ECU swap. I am at a loss.

Topic

[Daniel Weith]

Maybe put a vacuum gauge on to see what it looks like while holding it up at 5000, then dropping it down slowly to determine at what point a stall occurs..

One item Eric mentions in the vacuum diagnostics video is to remove the oxygen sensor if an exhaust blockage is suspected.

The hole in the CC may not be large enough, or maybe is collapsed inside before the hole after running for 1.5 hours..

[Mike]

You know, I thought about pulling the O2 sensor, and just didn’t thinking it wouldn’t be it…Well, thank you for the suggestion! Just pulled it out and bam!, car started right up and idles fine.

Ok, I have a new CC just haven’t installed it yet. Current one is welded one. Might look into cutting it out and putting new one on with clamps.

[Author]

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